It's curious that even with a dust limit of 5430 satoshi's, the network is still getting spammed to no end.
https://blockchain.info/address/1SochiWwFFySPjQoi2biVftXn8NRPCSQCNodes that receive these transactions will happily send out "inv" messages and relay them to other nodes, who respond with "getdata," also confirm the transactions as valid, and broadcast the transactions to everyone else. What if nodes had further logic to understand when these types of transactions are being created? Since they are essentially never going to confirm and are zero cost, it doesn't make sense for every node to be forced to broadcast them to begin with.
The solution won't necessarily be straightforward. A simple check such as [(sum of inputs)/(number of inputs) >5430 = true then send] might sound promising, but in practice it doesn't cut it because a spammer could just include one or several much larger outputs back to themselves as part of the overall transaction. Additionally, talking about any kind of limitation on the types of transactions that can be sent out strays into dangerous territory: no one wants to cripple the network.
But is it possible to nip this type of spam in the bud or are we stuck with it for all eternity? I'm imagining a future where dozens of unconfirmed transactions arrive into my account by the minute.